Why this rock is probably not a meteorite:

1) The density is too low for a meteorite - it's not heavy enough for it's size.

2) It is very hard; it scratched glass. None of the major minerals in meteorites scratch glass.

3) It appears to have fractured conchoidally, like glass. Meteorites don't fracture this way.

4) It is only weakly magnetic.  
What is it?

It's a piece of chert with a dark coating. Raman spectroscopy showed the the mineralogy to be quartz. Although the ouside is dark gray, when we cut it open it was light-colored inside. There was a 2-mm wide dark coating that was richer in magnetite and organic carbon.  We don't know how this rock obtained it's dark coating. Chert is common in Missouri, but it's usually cream colored, tan, light gray, or brown. 


Prepared by:

Randy L. Korotev

Department of Earth and Planetary Sciences
Washington University in St. Louis

Please don't contact me about the meteorite you think you’ve found until you read this and this.